HVAC & Ventilation
Cooling Load Estimation
Estimate total cooling load of a space considering solar gain, transmission, ventilation and internal heat sources (simplified method).
Units:
Rule of thumb: offices 60–90 W/m², server rooms 500–2000 W/m², retail 120–180 W/m². Add 20% safety margin. For accurate calculations use EN ISO 52016 or software (e.g. EnergyPlus, IDA ICE).
Q_total = Q_solar + Q_transmission + Q_ventilation + Q_people + Q_equipment
Input
Floor area iTotal floor area of the conditioned space in m².
m²
Ceiling height iClear ceiling height in metres.
m
Solar gain (glazing) iSolar heat gain through windows expressed per m² floor area. Large south-facing glazing: 50–80 W/m². Good shading: 15–30 W/m².
W/m²floor
Wall U-value (overall) iOverall heat transmission coefficient of building envelope. Modern: 0.15–0.30 W/m²K. Old: 0.5–1.0 W/m²K.
W/m²K
Indoor/outdoor ΔT iDifference between outdoor peak temperature and desired indoor temperature. Netherlands: outdoor 30°C, indoor 24°C → ΔT=6 K.
K
Number of persons iNumber of people in the space. Each person generates ≈70–120W sensible heat.
Equipment heat load iTotal heat dissipation from computers, servers, lighting, machinery etc. in Watts.
W
Result
Solar gain Q_solar [W]
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Transmission Q_trans [W]
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People Q_people [W]
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Equipment Q_equip [W]
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Total cooling load [W]
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Total cooling load [kW]
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Specific cooling load [W/m²]
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Compressor power (COP=3) [kW]
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